After looking at Starboard and Severne website, I found that Starboard's extension and uj use the 2-pin (US base) and Severne has only the Euro-pin type for the extension and uj. Is there any reason why this is so?

Is it true that PWA racers prefer the Euro-pin type and wave sailors prefer the 2-pin US base type?

Does anybody know if there is any difference in term of efficiency of these 2 types of joints?